Floor joint cover assembly

ABSTRACT

A cover assembly for a floor joint utilizes the combination of a bowed leaf spring spanning the joint and a coiled compression spring extending vertically in the joint to maintain an essentially stable holding bias on the cover plate of the assembly during relative shifting of the floor members of the joint caused by normal thermal effects on the members. The leaf spring is designed to break upon excessive movement of the floor members such as by earthquakes, thus releasing the cover plate before the latter can be permanently damaged.

United States Patent [191 Thom FLOOR JOINT COVER ASSEMBLY [75] Inventor:Wenzel W. Thom, Wichita, Kans.

[73] Assignee: Architectural Art Mfg., Inc.,

Wichita, Kans.

[22] Filed: Nov. 15, 1971 [21] Appl. No.: 198,602

[52] U.S. CI 52/98, 52/395, 52/466, 52/573, 94/18 [51] Int. Cl E04f15/14 [58] Field of Search 52/395, 396, 393, 52/401, 573, 466, 463,459,98, 461, 167; 94/18; 14/16 [56] References Cited UNITED STATES PATENTS3,394,639 7/1968 Viehmann 52/395 X 3,372,521 3/1968 Thom [111 3,745,726[451 July 17,1973

5/1970 Morgan 52/393 X 6/1972 Thom 52/573 X Primary Examiner-Price C.Faw, Jr. Attorney-Schmidt, Johnson, Hovey & Williams [57] ABSTRACT Acover assembly for a floor joint utilizes the combina tion of a bowedleaf spring spanning the joint and a coiled compression spring extendingvertically in the joint to maintain an essentially stable holding biason the cover plate of the assembly during relative shifting of the floormembers of the joint caused by normal thermal effects on the members.The leaf spring is designed to break upon excessive movement of thefloor members such as by earthquakes, thus releasing the cover platebefore the latter can be permanently damaged.

I 12 Claims, 8 Drawing Figures PATENIEDJUL 1 1 7 3'. 745.126

sum 1 or 2 INVENTOR.

WeflZel W Th am if; 3 WWMM eys PATENTEDJUL 1 "(I975 3745'726 sum 2 or 246a Fig.8.

a 35 a 54 Q INVENTOR.

wenzel W Thom This invention relates to an improved cover assembly forexpansion joints, particularly floor joints.

The cover plate of a floor joint cover assembly is exposed to constantdaily traffic over the floor. Accordingly, it is extremely importantthat the plate be held tightly against the floor over the joint so thatthe plate does not present a hazard to the moving traffic. Moreover, atight seal is important in preventing moisture and refuse from enteringthe joint.

Such a seal is difficult to maintain during relative shifting of thefloor members which define the joint, especially when the shiftingoccurs in irregular combinations of directions, commonly referred to asfour-way shifting. In the past many attempts have been made to providecover assemblies which perform in the desired manner, yet most haveresulted in assemblies which were less than satisfactory. For example,one concept was to use a yieldable leaf spring within the joint whichextended across the latter and was rigidly connected to the overlyingcover plate. In theory, the spring was to provide a yieldable holdingbias on the cover plate, even during expansion and contraction of thefloor member. In practice, the relatively thin aluminum cover platecould become deformed during expansion of the floor members because ofan excessive buildup of holding bias through the rigid connectionbetween the plate and leaf spring, thereby necessitating replacement orrepair of the damaged plate, both of which were undesirable from aneconomical standpoint. Similarly, upon contraction of the members towiden the joint, the holding bias on the cover plate was directlyreduced by a proportionate amount, thereby loosening the plate andincreasing the chances of accidents and moisture accumulation.

An additional problem inherent in prior assemblies was their lack ofsafeguards for major shifting of the floor members such as encounteredduring earthquakes as opposedto normal thermal expansion andcontraction. Because of the structural design of previous assemblies andthe positive manner in which the cover plates thereof were held inoverlying relationship to the joints, damage to the cover plates wasalmost certain to occur during such large-scale tremors, necessitatingcostly replacement of the cover plate and other components of theassembly as well. I

In view of the above problems, it is an important object of the presentinvention to provide a floorjoint assembly having opposed carriersections supporting a cover plate thereover which is held in position bythe yieldable interaction of a leaf spring spanning the joint and a coilspring extending vertically in the joint, such interaction resulting inthe maintenance of an essentially stable holding bias on the plate overthe normal range of thermally caused expansion and contraction of thestructural floor members of the joint.

Another important object of the invention is the provision of a leafspring as aforesaid which is designed to break along lines of bendthereof upon excessive relative shifting of the floor members, such asduring an earthquake, before the cover plate can be structurallydamaged, thereby releasing the plate.

A further important object of the present invention is to provide acover assembly as aforesaid having a vertical stabilizing post whichpasses through the leaf spring and permits canting of the latterrelative to the post during irregular, four-way shifting of the floormembers.

Still another important object of the instant invention is the provisionof means for precluding rotation of the post when the latteris'connected to the cover plate during installation of the assembly.

In the drawings:

FIG. 1 is a perspective, cross-sectional view of a floor jointinstallation utilizing a cover assembly constructed in accordance withthe principles of the present invention;

FIG. 2 is a fragmentary, top plan view of the installation of FIG. 1 ona reduced scale, portions of the cover plate thereof being broken awayto reveal components of the assembly therebelow;

FIG. 3 is a vertical, cross-sectional view of an installation utilizinga second embodiment of the present invention especially adapted forinstallations having joints smaller that that shown in FIG. 1;

FIG. 4 is a vertical cross-sectional view of the installation of FIG. 3illustrating the canting action of the assembly during four-way shiftingof the floor members;

FIG. 5 is an enlarged elevational view of components of the firstembodiment illustrating the relationship of the components in both thenormal and unstressed condition thereof;

FIG. 6 is a top plan view of the components of FIG.

FIG. 7 is a view similar to FIG. 5 of components of the secondembodiment'of the invention; and

FIG. 8 is a top plan view of the components of FIG. 7 similar to FIG. 6.

Referring initially to FIG. 1, a pair of solid structural members 10 areshown which comprise, for example, sections of the floor ofa building.The members 10 are illustrated as being constructed from cementitiousmaterial, although it is to be understood that the principles of thepresent invention are not limited to structural members of thisparticular construction. Members 10 are spaced apart to present an openjoint 12 therebetween, and each has an elongated, right angle carriersection 14 of the cover assembly integral therewith covering portions ofthe interior wall of the member 10 and the top margin of the latter.Sections 14 are identical in configuration and may be convenientlyconstructed of an extrudable material such as aluminum or the like, suchthat the somewhat irregular projections and channels on each section 14may be easily formed.

Sections 14 are preferably embedded in the respective floor members 10during construction of the latter, and a cavity 16 on each section 14between the vertical wall 18 and horizontal shelf 20 thereof extendslongitudinally of section 14 to capture a number of longitudinallyspaced nuts 22 for corresponding anchor bolts 24 embedded deeply withinthe corresponding floor member 10. A pair of opposed grooves 26 in thewalls 18 on opposite sides of joint 12 extend longitudinally of thelatter for supporting an optional, downwardly looped, conventional dripstrip (not shown) within joint 12. Each shelf 20 is disposed a shortdistance below the upper surface of the corresponding floor member 10and is provided with a short, upstanding hook-shaped wall 28. A pair ofvinyl or rubber sealing strips 30 are disposed on respective shelves 20interlocked with walls 28 and flush with the top surface of members 10.

The cover assembly also includes a flat, elongated cover plate 32 ofextruded aluminum or other suitable material which overlies joint 12 andhas a pair of downwardly extending ribs 34 along opposite side marginsthereof which are received within upwardly opening channels 36 in thesealing strips 30. The recessed nature of shelves 20 permit plate 32 tolie flush with the upper surfaces of the sealing strips 30, walls 28 andgroove members 10. A series of bowed, generally U- shaped, resilientleaf springs 38 of spring steel are disposed below plate 32 within joint12 at approximately 18 inch intervals, and each cooperates with a coilcompression spring 40 to exert holding bias on plate 32 through a post42 during relative shifting of the floor members 10. Spring 38 has apair of legs 44 interconnected by a bight 46 which, as shown clearly inFIG. 5, are capable of flexing toward and away from each other inresponse to inwardly directed pressure applied to the outside of thelegs 44. Legs 44 converge as the bight 46 is approached and lie againstopposed, sloping upper faces 48 of walls 18 when installed with theupper inturned tips 50 of legs 44 bearing against the underside of anoverhanging portion of each shelf 20. A pair of upturned stiffeningflanges 52 on opposite longitudinal sides of the bight 46 prevent thelatter from flexing during movement of the legs 44 toward or away fromone another.

The rigid, rectangular or hexagonal post 42 for each set of springs 38and 40 presents a plurality of flat sides 54 and has its upper interiorend threaded to receive a flathead bolt 56 projecting through the coverplate 32, whereby to firmly secure the post 42 to the plate 32. Post 42passes through a polygonal opening 58 in bight 46 having the same numberof sides as post 42 to preclude rotation of the latter relative tospring 38, yet permit linear movement of bight 46 along post 42.

The coil spring 40 is carried by the lower portion of post 42 extendingbeyond bight 46 and is trapped between a lower washer 60 affixed to post42 and the un derside of bight 46. An upper washer 62 affixed to post 42above bight 46 limits the travel of bight 46 in an upward directionalong post 42.

The installation shown in FIGS. 3, 4, 7 and 8 is identical to thatpreviously described, except in certain respects which adapt the secondembodiment for joints which are narrower than joint 12 of FIG. 1.Accordingly, components of the installation in FIGS. 3, 4, 7 and 8 areidentified by the same numerals used for the first embodiment with theaddition of the letter a. In view of the fact that the joint 12a isnarrower than joint 12, cover plate 32a is correspondingly narrower,post 42a is shorter than post 42, and springs 38a and 40a are smaller.Further, spring 38a has legs 44a and bight 46a which are rectilinear inconfiguration as opposed to the arcuate configuration of legs 44 andbight 46. In other structural and operational respects the twoinstallations are identical.

Prior to installation of the cover assembly, each leaf spring thereof isin its unstressed condition as illustrated by the widely extended legs44 of spring 38 in FIG. 5. However, when the apparatus of FIG. is placedwithin the joint 12, the legs 44 are forced to flex toward one anotherasufficient extent to allow spring 38 to be snapped in place as tips 50pass over the overhanging portion of the shelves into dispositiontherebeneath. After the cover plate 32 has been placed over joint 12with ribs 34 inserted into the channels 36 of sealing strips 30, thebolt 56 for each post 42 is threaded into the latter, causing the post42 to be drawn upwardly toward plate 32 against the biasing action ofsprings 38 and 40. Rotation of post 42 is prevented at this time becauseof the flat-sided configuration of post 42 and the similar configurationof opening 58. Once tightening of bolt 56 is completed, the assemblyassumes the normal, stressed condition illustrated in FIG. 1 and inphantom in FIG. 5.

Under the effects of normal thermally caused expansion and contraction,the floor members 10 move relatively toward or away from one anotherwithin a total range of approximately three-eighths inches. In the eventthat such movement is simply-toward one another in linear fashion toconstrict joint 12, legs 44 flex inwardly toward one another to urgebight 46 downwardly further into joint 12. If post 42 were rigidlysecured to spring 38, it is apparent that such action would cause abuildup of biasing energy in spring 38 directly proportional to themovement of members 10, such buildup, in turn, being transmitteddirectly to plate 32. Without release of the progressively accumulatingenergy, it is likely that plate 32 could be permanently deformed,necessitating repair or replacement. However, since bight 46 is movablealong post 42, such buildup is prevented from occurring as the springs38 and 40 interact to establish an equilibrium point. The resultantforce transmitted to post 42 and hence plate 32, is substantially lessthan that which would otherwise be applied to plate 32 if spring 38 andpost 42 were directly joined. Accordingly, over the normal displacementrange of three-eighths inches, the holding bias on plate 32 ismaintained in an essentially stable condition such that damage to plate32 is prevented.

Similarly, in the event that foor members 10 shift away from each otherto expand joint 12, the legs 44 are allowed to flex outwardly from theirnormal flexed condition of FIG. 1, tending to move bight 46 upwardlytoward plate 32. Once again, if post 42 and spring 38 were rigidlyinterconnected, such outward movement of legs 44 would substantiallyreduce the holding bias on plate 32. However, due to the shiftability ofspring 38 along post 42 and its interaction with spring 40, the biasactually released is substantially less than would otherwise take place,and essentially stable force is applied against plate 32.

In many situations, the members 10 are likely to move in a combinationof several different directions as illustrated in FIG. 4 wherein members10 are shifted in both horizontal and vertical planes relative to oneanother. This four-way shifting of members 10 has presented certainproblems in the past because of the inability of spring-retainingstructure within the joint to function properly under such distortedconditions. However, as illustrated by the spring 38a, the enlargeddimensions of opening 58a with respect to post 42a, permit spring 38a tocant relative to post 42a, thus relieving shear stress between post 42a,bolt 56a and cover plate 32a. Moreover, the inclined faces 48afacilitate such canting of the spring 38a at this time, and the springs38a and 40a interact to maintain essentially stable holding bias onplate 320.

While the leaf spring 38 cooperates with spring 40 to maintain stable,yieldable biasing pressure against plate 32, it also provides a meansfor releasing plate 32 under earthquake conditions before plate 32 canbe damaged. To this end, both embodiments of the springs 38 are temperedto a predetermined degree of brittleness suf flcient to cause the legs44 to break along the lines of weakness presented by the bendingjunction of legs 44 with bight 46 prior to a point at which excessivebias could be applied to plate 32. Once breakage has occurred, the plate32 is released and can be easily salvaged when the quake has subsided.Since the spring 38 is relatively inexpensive compared to the plate 32,this breakability feature affords a distinct economic advan' tage.

It is to be understood that various combinations of spring strengthscould be used to reach the desired interaction of springs 38 and 40during shifting of members l0. Regardless of which combination is chosenas best suited for the situation at hand, the fact that leaf spring 38is yieldably movable along post 42 instead of being rigidly affixedthereto, assures that substantially less energy buildup or releasethereof occurs than would otherwise be the case. Accordingly, over thenormal range of relative shifting of members 10, the holding bias onplate 32 is maintained in an essentially stable condition.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. A cover assembly for a joint defined by a pair of spaced-apart,relatively shiftable structural members, said assembly comprising:

a plate-like cover;

means supporting said cover in overlying relationship to said joint;

first yieldable biasing means disposed in spanning relationship withinthe joint having a pair of resilient legs on opposite sides of the jointand a shiftable portion between said legs, said first biasing meansbeing responsive to relative shifting of said members toward and awayfrom one another to flex said legs and move said shiftable portiontoward and away from said cover, to thereby vary the biasing energy ofsaid first biasing means,

second yieldable biasing means within said joint disposed for operationby said shiftable portion of said first biasing means during movementthereof, said second biasing means being coupled with said cover forbiasing the latter toward the joint, and said first and second biasingmeans interacting with one another during relative shifting of saidmembers to dissipate biasing energy otherwise accumulating in said firstbiasing means, thereby stabilizing the bias applied to said cover.

2. The assembly as claimed in claim 1, wherein is provided an elongated,rigid element on the cover projecting into said joint and supportingsaid second biasing means, said shiftable portion shifting relative tosaid element during movement toward and away from said cover to relaxand'compress said second biasing means.

3. The assembly as claimed in claim 2, wherein said portion of the firstbiasing means is provided with an opening receiving said element formovement of the portion therealong, said opening being enlarged withrespect to said element a sufficient extent to permit canting of saidfirst biasing means relative to the element.

4. The assembly as claimed in claim 2, wherein said portion of the firstbiasing means is provided with an opening receiving said element, saidelement and said portion being provided with mutually interengageablemeans for precluding rotation of said element within said opening.

5. The assembly as claimed in claim 4, wherein said element has aplurality of flat sides, said opening corresponding in configuration tothe element.

6. The assembly as claimed in claim 1, wherein said first biasing meansincludes a generally U-shaped, resilient component presenting a pair oflegs bendable toward and away from one another from opposite sides ofthe joint in response to corresponding shifting of said members and abight interconnecting said legs, and wherein is provided a rigid post onsaid cover, projecting into said joint through-said bight, said postbeing shiftably received by said bight for movement of the latter alongthe post in response to bending of said legs.

7. The assembly as claimed in claim 6, wherein is provided an abutmenton said post below said bight, said second biasing means beinginterposed between said abutment and said bight.

8. The assembly as claimed in claim 7, wherein said second biasing meansincludes a coil compression spring surrounding said post.

9. The assembly as claimed in claim 6, wherein is provided an opening insaid bight for the post, said opening being enlarged with respect tosaid post a sufficient extent to permit canting of said componentrelative to the post.

10. The assembly as claimed in claim 6, wherein said post has aplurality of flat sides, and wherein is provided an opening in saidbight for the post conforming in configuration to said post whereby topreclude relative rotation between the component and the post.

11. The assembly as claimed in claim 6, wherein is provided an elongatedflange integral with said bight and projecting outwardly therefrom, saidflange extending generally in the direction of bending movement of saidlegs to preclude corresponding bending of said bight to a sufficientextent to prevent binding of the bight on the post during movement ofthe bight therealong.

12. The assembly as claimed in claim 6, wherein said component isconstructed of material capable of breaking along the lines of bend ofsaid legs upon excessive relative shifting of said members, therebyreleasing said cover.

1. A cover assembly for a joint defined by a pair of spacedapart,relatively shiftable structural members, said assembly comprising: aplate-like cover; means supporting said cover in overlying relationshipto said joint; first yieldable biasing means disposed in spanningrelationship within the joint having a pair of resilient legs onopposite sides of the joint and a shiftable portion between said legs,said first biasing means being responsive to relative shifting of saidmembers toward and away from one another to flex said legs and move saidshiftable portion toward and away from said cover, to thereby vary thebiasing energy of said first biasing means, second yieldable biasingmeans within said joint disposed for operation by said shiftable portionof said first biasing means during movement thereof, said second biasingmeans being coupled with said cover for biasing the latter toward thejoint, and said first and second biasing means interacting with oneanother during relative shifting of said members to dissipate biasingenergy otherwise accumulating in said first biasing means, therebystabilizing the bias applied to said cover.
 2. The assembly as claimedin claim 1, wherein is provided an elongated, rigid element on the coverprojecting into said joint and supporting said second biasing means,said shiftable portion shifting relative to said element during movementtoward and away from said cover to relax and compress said secondbiasing means.
 3. The assembly as claimed in claim 2, wherein saidportion of the first biasing means is provided with an opening receivingsaid element for movement of the portion therealong, said opening beingenlarged with respect to said element a sufficient extent to permitcanting of said first biasing means relative to the element.
 4. Theassembly as claimed in claim 2, wherein said portion of the firstbiasing means is provided with an opening receiving said element, saidelement and said portion being provided with mutually interengageablemeans for precluding rotation of said element within said opening. 5.The assembly as claimed in claim 4, wherein said element has a pluralityof flat sides, said opening corresponding in configuration to theelement.
 6. The assembly as claimed in claim 1, wherein said firstbiasing means includes a generally U-shaped, resilient componentpresenting a pair of legs bendable toward and away from one another fromopposite sides of the joint in response to corresponding shifting ofsaid members and a bight interconnecting said legs, and wherein isprovided a rigid post on said cover, projecting into said joint throughsaid bight, said post being shiftably received by said bight formovement of the latter along the post in response to bending of saidlegs.
 7. The assembly as claimed in claim 6, wherein is provided anabutment on said post below said bight, said second biasing means beinginterposed between said abutment and said bight.
 8. The assembly asclaimed in claim 7, wherein said second biasing means includes a coilcompression spring surrounding said post.
 9. The assembly as claimed inclaim 6, wherein is provided an opening in said bight for the post, saidopening being enlarged with respect to said post a sufficient extent topermit canting of said component relative to the post.
 10. The assemblyas claimed in claim 6, wherein said post has a plurality of flat sides,and wherein is provided an opening in said bight for the post conformingin configuration to said post whereby to preclude relative rotationbetween the component and the post.
 11. The assembly as claimed in claim6, wherein is provided an elongated flange integral with said bight andprojeCting outwardly therefrom, said flange extending generally in thedirection of bending movement of said legs to preclude correspondingbending of said bight to a sufficient extent to prevent binding of thebight on the post during movement of the bight therealong.
 12. Theassembly as claimed in claim 6, wherein said component is constructed ofmaterial capable of breaking along the lines of bend of said legs uponexcessive relative shifting of said members, thereby releasing saidcover.